#define _CRT_SECURE_NO_WARNINGS 1
#include <cmath>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include<math.h>
#include<stdlib.h>
#include<stdio.h>
#include<unordered_map>
#include<queue>
using namespace std;

class Solution {
public:
    string removeDuplicates(string s) {
        string ret;
        ret.push_back(s[0]);
        int cur = 1;
        while (cur < s.size())
        {
            if (ret.size() && ret[ret.size() - 1] == s[cur]) ret.pop_back();
            else ret.push_back(s[cur]);
            cur++;
        }
        return ret;
    }
};

int main() {
    return 0;
}